Give it a new title. Your personal affection for the old title isn’t enough to risk confusion—or any stigma there might be in republishing a title that most likely went OP because it wasn’t selling anymore. We insiders know that the shelf life of the average novel is surprisingly short (2 to 3 years, although with ebooks the definition of “shelf life” is shifting), but the general public doesn’t know this. New content + new cover + new title + new pub year + new isbn = new book for a new audience. Embrace that and run with it.